The Provost Fellows and Scholars of the College of the Holy and Undivided Trinity of Queen Elizabeth, Near Dublin

University College Cork

The Provost, Fellows, Foundation Scholars & the Other Members of Board, of the College of the Holy & Undiv. Trinity of Queen Elizabeth, Near Dublin

John F Donegan

Wei-Hua Guo

Paul Martin Lambkin

Brian Corbett

Brendan John Roycroft

Edward Flood

Richard Phelan

Qiao-Yin Lu

The invention provides a system and method for measuring optical signal-to-noise-ratio (OSNR) in an optical communication system. A channel filter is adapted to select one specific optical communication channel from a wavelength-division-multiplexing (WDM) optical communication system, wherein the channel comprises an optical signal carrying digital bit information and noise from associated optical power amplifiers in the system. At least one optical delay interferometer is adapted to measure at least two interferograms of the noisy signal. The invention provides a mechanism for calculating the in-band OSNR from extinctions of the interferograms measured at different optical delays by referring to each other, wherein said optical delays are selected to be substantially less than a bit period of the optical channel. Because of the selection of the optical delays and/or the self-reference between the two measurements, the system can follow any changes happening to the signal such as additional filtering, self (cross)-phase modulation, the bias and drive signal change of the modulator used to generate the optical signal.

System and method for measuring optical signal-to-noise ratio

A tunable laser device () comprises integrally formed first and second ridge waveguides (). A longitudinally extending ridge () defines first and second light guiding regions () of the first and second waveguides () A plurality of first and second slots () extending laterally in the ridge () adjacent the first and second waveguides (), produce first and second mirror loss spectra of the respective first and second waveguides () with minimum peak values at respective first and second wavelength values. The spacing between the second slots () is different to that between the first slots () so that with one exception the minimum peak values of the first and second mirror loss spectrum occur at different wavelength values. The first and second waveguides () are independently pumped with variable currents to selectively vary the common wavelength at which the minimum peak values of the first and second mirror loss spectra occur to produce Vernier tuning of the device.

Tunable laser device and a method for producing light of respective selectable wavelengths

Growing community of inventors

Staffan, Ireland

John F Donegan